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Bomb_29390e
2 Intern
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193 Posts
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8239
May 18th, 2009 12:00
SP Owner
i have all of my LUN's owned by SPA. wonder if i can change a few of the LUN's to be owned by SPB and also check the "Auto Assignment enables' at each LUN!?
3601
1
Posted May 18th, 2009 13:00
First clarification - I copied the following from the Navisphere Help:
"Auto assign enables or disables (default) auto assign for a LUN. Auto assign controls the ownership of the LUN when an SP fails in a storage system with two SPs. You enable or disable auto assign for a LUN when you bind it. You can also enable or disable it after the LUN is bound without affecting the data on it.
With auto assign enabled, if the SP that owns the LUN fails and the server tries to access that LUN through the second SP, the second SP assumes ownership of the LUN to enable access. The second SP continues to own the LUN until the failed SP is replaced and the storage system is powered up. Then, ownership of the LUN returns to its default owner. If auto assign is disabled in this situation, the second SP does not assume ownership of the LUN, and access to the LUN does not occur.
If you are running failover software on a server connected to the LUNs in a storage system, you must disable auto assignment for all LUNs that you want the software to fail over when an SP fails. In this situation, the failover software, not auto assign, controls ownership of the LUN in a storage system with two SPs."3601
0
Posted May 18th, 2009 13:00
Next point - Yes, you can change SP ownership of your LUNs, but (and it is a huge but) if your LUNs are currently presented to a host, you could lose access if you do not have failover software properly running (e.g. PowerPath). Your zoning must also be correct or you may not be able to access the LUNs.
If you right click on a LUN and go to Properties, there are options related to ownership. You can change the default owner of each LUN you want to move, but that will not move the LUNs to the other SP. If you right click a LUN and select Trespass, the LUN will immediately change ownership.
You should do the necessary research to make sure you do not cause DL/DU during your ownership configurations.
Message was edited by:
brendm3601
1
Posted May 18th, 2009 13:00
PowerPath is failover software, I just did not want to assume you had it. If set up correctly (which is slightly different depending on the host - refer to admin guides on Powerlink for those details) you will not lose access to LUNs even if you lose access to one SP on the Clariion. Simply put, PowerPath can initiate a trespass as necessary.3601
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Posted May 18th, 2009 13:00
can you give an example of a failover software. i have the powerpath installed but not sure if this what u are talking about3601
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Posted May 19th, 2009 20:00
I would simply add that it isn't just PowerPath that needs to be configured correctly. You have to ensure that your host is configured correctly (there may be specific settings for HBA drivers on certain hosts types), that the drivers and patches are all up to date on the host, and that the initiators for that host are configured correctly on the array.3601
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Posted December 16th, 2009 19:00
Hi, I've noticed recently on new CX4's i've deployed that when I bind LUNs and set the SP owner to "auto", all LUNs are bound to one or the other SP, but not load balanced across both SP's. For example, I created 6 new LUNs with "auto" SP owner selected and all 6 LUNs are on SPB. How come?3601
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Posted December 17th, 2009 08:00
That's odd, I was just yesterday trying a test using thin LUNs and had to create 40 LUNs and needed them to be split between SPA and SPB - I select auto for SP owner and it did create all the LUNs split between A and B. I was using release 29 patch 003 (the latest release). What Raid Type did you use - my test was with Raid 5.
glen
848
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Posted December 17th, 2009 12:00
Were you using SATA disks? From the On-Line Help
Create LUN - Advanced Tab Note If the RAID group contains only ATA disks, Default Owner will be dimmed and unavailable.
glen
Create LUN - Advanced Tab 837
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Posted December 17th, 2009 12:00
I'll try it with R10 - not sure I can find a lab array with 40 unused disks
glen
kelleg
6 Operator
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4537 Posts
3601
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Posted May 20th, 2009 07:00
On the array the LUN ownership is determined when you bind a new LUN - you can assign the LUN an owner at that time - either SPA or SPB. The "Enable Auto-Assign" is used when you do not have failover software installed on your host - since you have PowerPath, you would not check this and any LUNs that you currently have on the array, you want to disable "auto-assign". The other consideration on the array is the failover mode setting - this by default is set to 1 - this is the setting for PowerPath - if you do not have failover software installed on a host, this setting should be zero (0).
Now, on the host you have two versions of PowerPath - Licensed and Unlicensed. If you have the free (Unlicensed) version installed it will ONLY support ONE HBA and TWO Paths to the array - one to SPA and one to SPB - this provides for basic array failover protection. The Licensed version supports more HBA's and more paths and load balancing. To see what version you have installed, use the powermt commands:
"powermt check_registration"
On the array, you need to balance the owership of the LUNs between SPA and SPB to achieve load balance. If all the LUNs are owned by SPB you need to determine which LUNs to move to SPA, then Change the owership (Default Owner) to SPA and from the host run the "powermt restore dev=all" command - this will trespass the LUN to the default owner - this way PowerPath knows where the LUN should be.
Remember that most of this is in the On-Line Help when you're in Navisphere.
glen